feat(计算): 添加计算表达式

app/build.gradle

@@ -54,6 +54,7 @@ dependencies {
     debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"
     debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_version"
 
+    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation 'androidx.core:core-ktx:1.8.0'
     implementation "androidx.compose.ui:ui:$compose_version"
     implementation "androidx.compose.ui:ui-tooling-preview:$compose_version"
@@ -70,4 +71,8 @@ dependencies {
     implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.4.1'
 
     implementation "com.apkfuns.logutils:library:1.7.5"
+    /**
+     * https://github.com/uklimaschewski/EvalEx
+     */
+    implementation "com.udojava:EvalEx:2.7"
 }

app/src/main/java/com/jyn/composecalculator/DateViewModel.kt

@@ -4,9 +4,9 @@ import android.app.Application
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.AndroidViewModel
+import com.udojava.evalex.Expression
 
 class DateViewModel(application: Application) : AndroidViewModel(application) {
-    var idpPortrait = true
     var textBoxHeight = 0.dp
     var inputText = mutableStateOf("")
     var resultText = mutableStateOf("")
@@ -22,9 +22,22 @@ class DateViewModel(application: Application) : AndroidViewModel(application) {
 
     fun clear() {
         inputText.value = ""
+        resultText.value = ""
     }
 
     fun calculate() {
-        resultText.value = "XXXXX"
+        val expr = inputText.value.replace('×', '*').replace('÷', '/')
+        val expressions = arrayOf('+', '-', '*', '/')
+        if (expr.isEmpty()) return
+        if (!expressions.any { expr.contains(it) }) {
+            return
+        }
+        if (expressions.any { expr.endsWith(it) }) {
+            resultText.value = ""
+            return
+        }
+        val eval = Expression(expr).eval()
+
+        resultText.value = eval.toString()
     }
 }

build.gradle

@@ -1,7 +1,7 @@
 buildscript {
     ext {
         compose_version = '1.2.0-rc01'
-        kotlin_version = '1.7.1'
+        kotlin_version = '1.6.0'
     }
 }// Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {